JP4424245B2 - Engine start control device and engine start control method for hybrid vehicle - Google Patents

Description

  The present invention relates to an engine start control device and an engine start control method for a hybrid vehicle using an engine and a motor as driving force generation sources.

Conventionally, in a hybrid vehicle in which an engine and a motor are connected via an engine clutch and the engine is started by the motor, a friction clutch is used as the engine clutch, and the engine and the motor are slip-engaged at the time of starting the engine. The accompanying driving force fluctuation is suppressed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 10-68335

  However, the conventional technology has a problem that the initial explosion torque of the engine is transmitted to the driving force synthesizing transmission or the motor, and the driving force fluctuates.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide an engine start control device and an engine start control method for a hybrid vehicle that can suppress fluctuations in driving force due to the initial explosion torque transmission of the engine. There is.

In order to achieve the above object, in the engine start control method for a hybrid vehicle according to the present invention, a driving force combining transmission having an engine and a motor as driving force generation sources and connecting at least the motor and an output member; An engine clutch that directly or indirectly connects the motor, a hydraulic command value calculation unit that commands a hydraulic pressure for adjusting the engagement of the engine clutch, and an engine start control unit that starts the engine by engaging the engine clutch. In hybrid vehicles,
When the engine is started , the slip amount of the engine clutch is increased when the actual engine speed becomes higher than the clutch input speed which is the motor side speed of the engine clutch.

In the present invention, the initial explosion torque of the engine is consumed as frictional heat by the engine clutch and is not input to the driving force combining transmission. That is, since engine clutch slip is converted into frictional heat, transmission of engine torque exceeding the engagement capacity of the engine clutch can be prevented. Thus, fluctuations in driving force due to the initial explosion torque of the engine can be suppressed.

  Hereinafter, the best mode for realizing an engine start control device for a hybrid vehicle of the present invention will be described based on Examples 1 and 2 shown in the drawings.

First, the configuration will be described.
[Drive system configuration of hybrid vehicle]
FIG. 1 is an overall system diagram illustrating a drive system of a hybrid vehicle according to a first embodiment. As shown in FIG. 1, the drive system of the hybrid vehicle in the first embodiment includes an engine E, a first motor generator MG1 (motor), a second motor generator MG2 (motor), and an output gear OG (output member). And a driving force synthesis transmission TM.

  The engine E is a gasoline engine or a diesel engine, and the opening degree of a throttle valve and the like are controlled based on a target engine torque command from an engine controller 1 described later.

  The first motor generator MG1 and the second motor generator MG2 are synchronous motor generators in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. This synchronous motor generator comprises a first motor generator MG1 composed of an outer rotor OR and a stator S out of a multilayer motor CM in which an inner rotor IR, a stator S and an outer rotor OR are overlapped in the radial direction. The OR and stator S constitute a second motor generator MG2. The inner rotor IR and the outer rotor OR are independently controlled by applying a three-phase alternating current generated by the inverter 3 to the stator S based on a control command from a motor controller 2 described later.

  The driving force synthesis transmission TM has a Ravigneaux type planetary gear train PGR and a low brake LB. The Ravigneaux planetary gear train PGR has a first sun gear S1, a first pinion P1, and a first ring gear R1. And the second sun gear S2, the second pinion P2, the second ring gear R2, and the common carrier PC that supports the first pinion P1 and the second pinion P2 that mesh with each other. That is, the Ravigneaux type planetary gear PGR has five rotating elements: the first sun gear S1, the first ring gear R1, the second sun gear S2, the second ring gear R2, and the common carrier PC. The connection relationship of the input / output members with respect to these five rotating elements will be described.

  A first motor generator MG1 is connected to the first sun gear S1. The first ring gear R1 is provided so as to be fixed to the case via a low brake LB. A second motor generator MG2 is connected to the second sun gear S2. An engine E is connected to the second ring gear R2 via an engine clutch EC. An output gear OG is directly connected to the common carrier PC. A driving force is transmitted from the output gear OG to the left and right driving wheels via a differential and a drive shaft (not shown).

2, the first motor generator MG1 (first sun gear S1), the engine E (second ring gear R2), the output gear OG (common carrier PC), the low brake LB (first It is possible to introduce a rigid lever model that is arranged in the order of 1 ring gear R1) and second motor generator MG2 (second sun gear S2) and can simply express the dynamic operation of the Ravigneaux planetary gear train PGR.

  Here, the “collinear diagram” is a velocity diagram used in a simple and easy-to-understand method of drawing instead of the method of obtaining by equation when considering the gear ratio of the differential gear, The rotation number (rotation speed) of the rotation element is taken, each rotation element is taken on the horizontal axis, and the interval between each rotation element is arranged so as to be a collinear lever ratio based on the gear ratio of the sun gear and the ring gear. .

  The engine clutch EC and the low brake LB are a multi-plate friction clutch and a multi-plate friction brake that are fastened by hydraulic pressure from a hydraulic control device 5 to be described later. The engine clutch EC is the engine E in the collinear diagram of FIG. The low brake LB is arranged at a position that coincides with the rotational speed axis of the second ring gear R2, and the low brake LB has a rotational speed axis of the first ring gear R1 (second rotational speed axis of the output gear OG (Position between the rotational speed axis of the sun gear S2).

[Hybrid vehicle control system configuration]
As shown in FIG. 1, the control system of the hybrid vehicle in the first embodiment includes an engine controller 1, a motor controller 2, an inverter 3, a battery 4, a hydraulic control device 5, and an integrated controller (engine start control means). 6, an accelerator opening sensor 7, a vehicle speed sensor 8, an engine speed sensor 9, a first motor generator speed sensor 10, a second motor generator speed sensor 11, and a second ring gear speed sensor 12. , And is configured.

  The engine controller 1 responds to a target engine torque command from the integrated controller 6 that inputs the accelerator opening AP from the accelerator opening sensor 7 and the engine speed Ne from the engine speed sensor 9, in accordance with the engine operating point (Ne, A command for controlling Te) is output to, for example, a throttle valve actuator (not shown).

  The motor controller 2 operates the motor of the first motor generator MG1 in response to a target motor generator torque command from the integrated controller 6 that inputs motor generator rotation speeds N1 and N2 from both motor generator rotation speed sensors 10 and 11 by a resolver. A command (device control signal) for independently controlling the point (N1, T1) and the motor operating point (N2, T2) of the second motor generator MG2 is output to the inverter 3. The motor controller 2 outputs information on the battery S.O.C representing the state of charge of the battery 4 to the integrated controller 6.

  The inverter 3 is connected to the respective stator coils of the first motor generator MG1 and the second motor generator MG2, and generates an independent three-phase alternating current according to a command from the motor controller 2. The inverter 3 is connected to a battery 4 that is discharged during power running and charged during regeneration.

  The hydraulic control device 5 receives a hydraulic command from the integrated controller 6 and performs engagement hydraulic pressure control and release hydraulic pressure control of the engine clutch EC and the low brake LB. The engagement hydraulic pressure control and the release hydraulic pressure control include a half-clutch control based on the slip engagement control and the slip release control.

  The integrated controller 6 includes an accelerator opening AP from the accelerator opening sensor 7, a vehicle speed VSP from the vehicle speed sensor 8, an engine speed Ne from the engine speed sensor 9, and a first motor generator speed sensor 10. Information such as the first motor generator rotational speed N1, the second motor generator rotational speed N2 from the second motor generator rotational speed sensor 11, the engine input rotational speed ωi from the second ring gear rotational speed sensor 12, and the like. Predetermined arithmetic processing is performed. Then, a control command is output to the engine controller 1, the motor controller 2, and the hydraulic control device 5 according to the calculation processing result.

  The integrated controller 6 and the engine controller 1 and the integrated controller 6 and the motor controller 2 are connected by bidirectional communication lines 14 and 15 for information exchange, respectively.

[Driving mode of hybrid vehicle]
The travel modes in the hybrid vehicle of the first embodiment include an electric vehicle continuously variable transmission mode (hereinafter referred to as “EV mode”), an electric vehicle fixed transmission mode (hereinafter referred to as “EV-LB mode”), and a hybrid. It has a vehicle fixed speed change mode (hereinafter referred to as “LB mode”) and a hybrid vehicle continuously variable speed change mode (hereinafter referred to as “E-iVT mode”). The “EV mode” and the “EV-LB mode” are “electric vehicle travel mode”, and the “LB mode” and the “E-iVT mode” are “hybrid vehicle travel mode”.

  The “EV mode” is a continuously variable transmission mode in which only two motor generators MG1 and MG2 run as shown in the collinear diagram of FIG. 2 (a), and the engine E is driven (minimum speed control). The engine clutch EC is released.

  The “EV-LB mode” is a fixed speed change mode in which only the two motor generators MG1 and MG2 run with the low brake LB engaged, as shown in the collinear diagram of FIG. E is drive (minimum speed control) and the engine clutch EC is released. Since the reduction ratio from the first motor generator MG1 to the output Output and the reduction ratio from the second motor generator MG2 to the output Output are large, this is a mode in which a large driving force is generated.

  As shown in the collinear diagram of FIG. 2 (c), the “LB mode” is a fixed speed change mode in which the engine E and the motor generators MG1 and MG2 travel with the low brake LB engaged. The engine clutch EC is engaged during operation. This is a mode in which the driving force is large because the reduction ratio from the engine E and the motor generators MG1, MG2 to the output Output is large.

  The “E-iVT mode” is a continuously variable transmission mode in which the engine E and the motor generators MG1 and MG2 run as shown in the nomogram of FIG. 2 (d). The engine E is operated and the engine clutch EC is It is conclusion.

  Then, the mode transition control of the four travel modes is performed by the integrated controller 6. That is, the integrated controller 6 has a travel mode in which the four travel modes as shown in FIG. 3 are allocated to the three-dimensional space by the required driving force Fdrv (determined by the accelerator opening AP), the vehicle speed VSP, and the battery SOC. When the vehicle is stopped or running, the driving mode map is searched based on the detected values of the required driving force Fdrv, vehicle speed VSP, and battery SOC, and the vehicle operating point determined by the required driving force Fdrv and vehicle speed VSP. The optimum driving mode is selected according to the battery charge amount. FIG. 3 is an example of a travel mode map represented by a two-dimensional representation of the required driving force Fdrv and the vehicle speed VSP by cutting out the three-dimensional travel mode map at a value with a sufficient capacity range of the battery S.O.C.

  When mode transition is performed between the “EV mode” and the “EV-LB mode” by selecting the travel mode map, the low brake LB is engaged / released as shown in FIG. When mode transition is performed between the “E-iVT mode” and the “LB mode”, the low brake LB is engaged / released as shown in FIG. Further, when the mode transition is performed between the “EV mode” and the “E-iVT mode”, the engagement / release of the engine clutch EC is performed as shown in FIG. When mode transition is performed between the “EV-LB mode” and the “LB mode”, the engine clutch EC is engaged / released as shown in FIG.

Next, the operation will be described.
[Engine clutch engagement control process at engine start]
FIG. 5 is a flowchart showing a flow of engine clutch engagement control processing at the time of engine start executed by the integrated controller 6 of the first embodiment, and each step will be described below. This control process is executed every predetermined control cycle.

  In step S1, it is determined whether or not there is an engine start request, that is, whether or not a mode request for the LB mode or the E-iVT mode is made during traveling in the EV mode or the EV-LB mode. If yes, then go to step S2, if no, go to return.

  In step S2, in order to improve the initial pressure increase response of the engine clutch EC, a precharge hydraulic pressure command value is output to the hydraulic pressure control device 5, and the process proceeds to step S3.

  In step S3, it is determined whether or not precharge is completed. If YES, the process proceeds to step S4. If NO, the process proceeds to step S2. Here, completion of the precharge is determined, for example, based on whether or not a predetermined precharge set time has elapsed since the transition to the precharge phase. Steps S2 and S3 are precharge phases.

  In step S4, a shelf pressure holding hydraulic pressure command lower than the precharge hydraulic pressure command value is output to the hydraulic pressure control device 5, and the process proceeds to step S5. This shelf pressure maintenance is performed to prevent the start of engagement of the engine clutch EC during the precharge phase.

  In step S5, it is determined whether or not shelf pressure holding is completed. If YES, the process proceeds to step S6. If NO, the process proceeds to step S4. Steps S4 and S5 are set as a shelf pressure holding phase. Here, the completion of the shelf pressure holding is determined, for example, based on whether or not a predetermined shelf pressure holding set time has elapsed since the transition to the shelf pressure phase.

  In step S6, a hydraulic pressure command value that gives a predetermined increasing gradient, that is, a hydraulic pressure command value slightly larger than the previous value is output to the hydraulic pressure control device 5, and the process proceeds to step S7.

  In step S7, it is determined whether or not the engine speed Ne detected by the engine speed sensor 9 has exceeded the set speed A. If YES, the process proceeds to step S8, and if NO, the process proceeds to step S6. Steps S6 and S7 are defined as a first hydraulic ramp control phase.

  In step S8, the target engine speed is set (corresponding to the target engine speed setting means), and at the same time, the engine speed Ne detected by the engine speed sensor 9 and the target engine speed are detected with respect to the hydraulic control device 5. A hydraulic pressure command value that eliminates the deviation is output, and the process proceeds to step S9. A method for setting the target engine speed will be described later.

  In step S9, the difference between the clutch rotational speed obtained from the engine input rotational speed ωi detected by the second ring gear rotational speed sensor 12 and the engine rotational speed detected by the engine rotational speed sensor 9 is smaller than the first deviation B. It is determined whether or not. If YES, the process moves to step S10, and if NO, the process moves to step S8. Steps S8 and S9 are set as a feedback control phase.

  In step S10, a hydraulic pressure command value that gives a predetermined increasing gradient is output to the hydraulic pressure control device 5, and the process proceeds to step S11.

  In step S11, the difference between the clutch rotational speed obtained from the engine input rotational speed ωi detected by the second ring gear rotational speed sensor 12 and the engine rotational speed detected by the engine rotational speed sensor 9 is smaller than the second deviation C. It is determined whether or not. If YES, the process proceeds to step S12. If NO, the process proceeds to step S10. Steps S10 and S11 are set as the second lamp control phase.

  In step S12, a hydraulic pressure command value for completely engaging the engine clutch EC is output to the hydraulic pressure control device 5, and the process proceeds to return.

[Set target engine speed]
In the first embodiment, in the feedback control phase, a lower limit value is set for the target engine speed in order to prevent engine stall due to a hydraulic pressure follow-up delay with respect to the hydraulic pressure command value. This lower limit value is set to a rotation speed that avoids the occurrence of engine stall, that is, a rotation speed that avoids the vicinity of zero. Further, in order to avoid the transmission of the initial explosion torque of the engine to the second ring gear R2, it is set to be equal to or less than the clutch rotational speed (second ring gear rotational speed).

  Further, as shown in FIG. 6, the target engine speed is changed in accordance with the engine water temperature. Furthermore, by setting a value that avoids the number of revolutions in the resonance frequency region of the engine damper, the engine mount, or the like, it is possible to suppress vehicle body vibration at the time of starting the engine.

  A high value is set when the engine water temperature is lower than the predetermined temperature, and a low value is set when the engine water temperature is equal to or higher than the predetermined water temperature. That is, since the engine friction is large at a low water temperature, the target engine speed is set high so that engine stall does not occur during feedback control to the target engine speed.

[Engine mode setting control processing]
FIG. 7 is a flowchart showing the flow of the engine mode control process executed by the integrated controller 6 according to the first embodiment. Each step will be described below. This control process is executed every predetermined control cycle.

  In step S21, it is determined whether there is an engine start request. If YES, the process proceeds to step S22, and if NO, the process proceeds to step S25.

  In step S22, it is determined from the engine speed Ne detected by the engine speed sensor 9 whether the engine E has started to rotate. If YES, the process proceeds to step S23, and if NO, the process proceeds to step S25.

  In step S23, it is determined whether or not the engine speed Ne is larger than the value obtained by adding the set engine speed X to the target engine speed (corresponding to engine complete explosion determination means). If YES, the process proceeds to step S24, and if NO, the process proceeds to step S26.

  In step S24, the engine mode is set to the engine mode after the complete explosion determination, and the process proceeds to return. Here, the engine mode after complete explosion determination is the engine operating point (Ne) according to the target engine torque command calculated from the accelerator opening AP from the accelerator opening sensor 7 and the engine speed Ne from the engine speed sensor 9. , Te) is the engine mode that controls.

  In step S25, a fuel cut request is output to the engine controller 1, and the process proceeds to return.

  In step S26, the engine mode is set to the engine mode at start, and the process proceeds to return. Here, the engine mode at start-up is an engine mode that consists of a cranking mode and a firing (ignition) mode until the engine E is completely detonated.

[Problems in engine clutch torque control]
In a hybrid vehicle that starts an engine with a motor generator, a ramp control that gradually increases an engine clutch engagement capacity at the time of starting the engine is used to suppress the occurrence of shock due to engine torque fluctuation. However, in this ramp control, since the clutch engagement capacity at the time of the first engine explosion has already increased to near the maximum capacity, the engine initial explosion torque is input from the engine clutch, and a driving force fluctuation occurs.

  Even in the case of ramp control, it is possible to avoid the input of the initial explosion torque of the engine by setting the increasing gradient of the hydraulic pressure command value gently. However, there is a problem that the rise of the driving force is delayed.

  On the other hand, Japanese Patent Laid-Open No. 2000-71815 includes a motor for starting an engine directly connected to an engine, and the engine clutch is engaged after the engine rotation is synchronized with the rotation of the engine clutch, thereby preventing a fastening shock. The technology is described. However, since this prior art requires a motor for starting the engine, it cannot be applied to a system configured as in Embodiment 1 in which the engine is started by the output of the motor generator without using the motor for starting the engine.

[Driving force fluctuation suppression effect by engine clutch speed control]
In contrast, in the first embodiment, in the feedback control phase at the time of engine start, a target engine speed that is equal to or lower than the clutch speed (second ring gear speed) is set, and the actual engine speed matches the target engine speed. Thus, the hydraulic pressure command value of the engine clutch EC is set. Specifically, the clutch torque is reduced when the engine speed increases more than necessary, and the clutch torque is increased when the engine speed decreases more than necessary.

Therefore, prevention in the feedback control phase, when the rotational speed of the engine caused by the initial combustion torque of the engine E is increased more than necessary, to reduce the torque capacity of the engine clutch EC, the transmission of the engine torque in excess of the value Therefore, it is possible to avoid the initial explosion torque of the engine E from being input to the driving force combining transmission TM from the second ring gear R2.

  That is, the engine start control device of the first embodiment is a system that starts the engine by the output of the motor generator without using the engine start motor in order to control the engagement capacity of the engine clutch EC according to the clutch rotational speed. Nevertheless, it is possible to realize control in which the clutch is engaged after the engine rotation is synchronized with the clutch rotation.

  Further, in the first embodiment, since the shift to the second ramp phase in which the hydraulic pressure command value is increased from the time when the actual engine speed approaches the clutch speed, the rising of the driving force is not delayed with respect to the driving force request.

FIG. 8 is a time chart showing the driving force fluctuation suppressing effect of the first embodiment.
At time t1, the hydraulic engagement phase becomes a precharge phase in response to the engine start request, and precharge to the engine clutch EC is started. At this time, the engine mode becomes the cranking mode, and cranking is started.

  At time t2, the precharge is completed and the process proceeds to the shelf pressure holding phase, and the hydraulic pressure command value is held at a predetermined shelf pressure.

  At time t3, the shelf pressure holding is completed, and the process proceeds to the first hydraulic ramp control phase in which the hydraulic pressure command value is set to a predetermined increase gradient.

  At time t3 ′, the engine mode shifts from the cranking mode to the firing mode as the engine speed increases.

At time t4, since the engine speed has exceeded the set speed A, the process shifts to the feedback control phase, and a hydraulic pressure command value that matches the actual engine speed with the target engine speed is output. At this time, the target engine speed to be set below the clutch rotational speed, there is no possibility that the engine rotational speed greatly exceeds the clutch rotational speed. Therefore, the initial explosion torque of the engine is consumed as frictional heat by the engine clutch EC and is not input to the driving force combining transmission TM.

  Further, in the feedback control phase, the hydraulic pressure command value is set to be equal to or greater than the lower limit value, so that it is possible to prevent the engine stall from occurring due to a decrease in the engine speed to near zero with a delay in following the hydraulic pressure with respect to the hydraulic pressure command value.

  At time t4 ′, the engine speed becomes equal to or higher than the set engine speed X than the target engine speed, and the engine mode shifts from the firing mode to the complete explosion mode.

  At time t5, the difference between the clutch rotational speed and the engine rotational speed becomes smaller than the first deviation B, the process proceeds to the second ramp control phase, and control is performed to increase the hydraulic pressure command value with a predetermined gradient.

  At time t6, the difference between the clutch rotational speed and the engine rotational speed becomes smaller than the second deviation C, and a hydraulic pressure command value for completely engaging the engine clutch EC is output.

Next, the effect will be described.
In the engine start control device of the hybrid vehicle of the first embodiment, the effects listed below can be obtained.

(1) When the engine is started, the engine controller includes target engine speed setting means (step S8) for setting a target engine speed that is equal to or lower than the clutch input speed that is the motor side speed of the engine clutch EC. When the engine speed becomes larger than the clutch input speed that is the motor side speed of the engine clutch EC, the slip amount of the engine clutch EC is increased . Therefore, it is possible to avoid the initial explosion torque of the engine from being input to the driving force synthesizing transmission TM via the engine clutch EC, and the driving force fluctuation can be suppressed.

  (2) The integrated controller 6 sets the hydraulic pressure command value based on the deviation between the target engine speed and the actual engine speed. Therefore, when the engine speed increases more than necessary, the clutch torque can be reduced, and when the engine speed decreases more than necessary, the clutch torque can be increased. Both explosion torque transmission and engine stall can be avoided.

  (3) Since the target engine speed setting means sets a lower limit value for the hydraulic pressure command value, even in a system in which the actual torque delay of the engine clutch EC occurs with respect to the hydraulic pressure command value, the clutch torque is set in a followable region. The engine stall can be avoided because it can be set.

  (4) The engine start control means includes a precharge phase that outputs a precharge hydraulic pressure command value until the clutch piston stroke ends when the engine clutch EC shifts from the released state to the engaged state, and the actual engine rotation. And a feedback control phase that outputs a hydraulic pressure command value that matches the number with the target engine speed, and the target engine speed setting means sets a lower limit value for the hydraulic pressure command value during the feedback control phase. Therefore, since the lower limit value of the hydraulic pressure command value is provided after the initial operation in the precharge phase (including the shelf pressure holding phase in the first embodiment), engine stall in a system in which clutch torque is set by hydraulic pressure can be avoided.

  (5) Equipped with engine complete explosion determination means (engine complete explosion determination means) that determines that the engine is in a complete explosion state when the actual engine speed is higher than the target engine speed by X or more. When it is determined that the engine is in the complete explosion state, the controller 6 switches the engine control mode from the engine mode at start-up to the engine mode after complete explosion. Therefore, since the complete explosion determination can be performed at the timing when the engine reaches the complete explosion state, the engine control mode can be switched optimally.

(6) The target engine speed setting means sets the target engine speed to a higher value when the engine water temperature is low than when the engine water temperature is high. because it can set a high number, it is possible to avoid the occurrence of an engine stall when the large amount of slip of the engine clutch EC.

  (7) When the difference between the actual engine speed and the clutch input speed is less than or equal to the first deviation B, the engine start control means shifts to the second ramp control phase that gradually increases the hydraulic pressure command value. Since the restarting of the engagement force is started when the engine rotation and the clutch rotation approach each other, it is possible to avoid the occurrence of a shock when the clutch is engaged.

  The second embodiment is different from the first embodiment in the transition timing from the feedback control phase to the second ramp control phase, the engine complete explosion determination condition, and the target engine speed setting condition. Since the configuration is the same as that of the first embodiment, the description thereof is omitted.

Next, the operation will be described.
[Target engine speed according to clutch oil temperature]
In the second embodiment, as shown in FIG. 9, the target engine speed is changed according to the clutch oil temperature (clutch temperature). Further, it is the same as in the first embodiment in that it is set to a value that avoids the number of revolutions in the resonance frequency region of the engine damper, the engine mount, etc., and the vehicle body vibration is suppressed.

  The clutch oil temperature is set to a high value when the temperature is higher than the predetermined temperature, and is set to a low value when the clutch oil temperature is equal to or lower than the predetermined temperature. In other words, the optimal target engine rotation with respect to the clutch oil temperature varies depending on the characteristics of the clutch. However, when the responsiveness of the clutch oil pressure deteriorates at high temperatures, the target engine rotation is avoided in order to avoid engine stall due to the oil pressure follow-up delay. Set the rotation speed higher.

[Timing to enter the second ramp control phase]
In the second embodiment, the transition timing from the feedback control phase to the second ramp control phase is determined from the difference between the actual engine speed and the clutch speed and the time. That is, in step S9 of FIG. 5, when the time during which the difference between the actual engine speed and the clutch speed is equal to or less than the first deviation B continues for the second set time or longer, the process proceeds to the second ramp control. As a result, when the engine rotational speed becomes stable in the vicinity of the clutch rotational speed, the restart of the clutch engagement force can be started, so that the occurrence of a shock at the time of clutch engagement can be avoided.

[Engine complete explosion judgment condition]
Further, in the second embodiment, in step S23 of FIG. 8, when the state where the actual engine speed is higher than the target engine speed by the set speed X or more continues for the first set time or longer, the engine is in a complete explosion state. Judgment is made and the engine mode is shifted to the engine mode after the complete explosion. Thus, since the engine control mode is switched when the engine is in a state where torque can be stably generated, the engine start-time control (start-up engine mode) time can be set as necessary.

Next, the effect will be described.
In the engine start control device for the hybrid vehicle of the second embodiment, the effects listed below can be obtained in addition to the effects (1) to (5) and (7) of the first embodiment.

(8) The target engine speed setting means sets the target engine speed to a higher value when the clutch oil temperature is high than when the clutch oil temperature is low . The engine stall due to the oil pressure follow-up delay can be suppressed.

  (9) The engine complete explosion determination means determines that the engine is in the complete explosion state when the state where the actual engine rotational speed is higher than the target engine rotational speed by at least the set rotational speed X continues for the first set time or longer. The engine starting control (starting engine mode) time can be set as required.

  (10) The engine start control means is a second ramp control for gradually increasing the hydraulic pressure command value when a time during which the difference between the actual engine speed and the clutch speed is equal to or less than the first deviation continues for the second set time or longer. Since shifting to the phase, it is possible to avoid the occurrence of shock when the clutch is engaged.

(Other examples)
As mentioned above, although the engine start control device of the hybrid vehicle of the present invention has been described based on the first and second embodiments, the specific configuration is not limited to the first and second embodiments. Design changes and additions are permitted without departing from the scope of the claimed invention.

  For example, in the first and second embodiments, an example of a hybrid vehicle with an engine clutch having an engine and two motor generators as a driving force generation source is shown. However, the present invention relates to an engine and one or more motors as a driving force generation source. And can be applied to a hybrid vehicle that starts the engine with the driving force of a motor by an engine clutch. Moreover, although the example which has a Ravigneaux type planetary gear train as a driving force synthetic | combination transmission was shown, for example, it can apply also to the driving force synthetic | combination transmission which has a differential apparatus etc. provided with several simple planetary gear trains. .

1 is an overall system diagram showing a hybrid vehicle of Example 1. FIG. FIG. 3 is a collinear diagram showing each traveling mode by a Ravigneaux planetary gear train employed in the hybrid vehicle of the first embodiment. It is a figure which shows an example of the driving mode map in the hybrid vehicle of Example 1. FIG. It is a figure which shows the mode transition path | route between the four driving modes in the hybrid vehicle of Example 1. FIG. 6 is a flowchart showing a flow of engine clutch engagement control processing at the time of engine start executed by the integrated controller 6 of the first embodiment. 3 is a setting map of a target engine speed according to the engine water temperature according to the first embodiment. 6 is a flowchart illustrating a flow of an engine mode control process executed by the integrated controller 6 according to the first embodiment. 3 is a time chart illustrating a driving force fluctuation suppressing effect of the first embodiment. 6 is a setting map of a target engine speed according to the clutch temperature of the second embodiment.

Explanation of symbols

E engine
MG1 1st motor generator (motor)
MG2 Second motor generator (motor)
OG output gear (output member)
TM Driving force transmission
PGR Ravigneaux type planetary gear train
EC engine clutch
LB Low brake 1 Engine controller 2 Motor controller 3 Inverter 4 Battery 5 Hydraulic control device 6 Integrated controller 6a Target rotational speed calculation section 6b Torque command value setting section 7 Accelerator opening sensor 8 Vehicle speed sensor 9 Engine rotational speed sensor 10 First motor generator Speed sensor 11 Second motor generator speed sensor 12 Second ring gear speed sensor

Claims (11)

A driving force generating transmission having an engine and a motor as a driving force generation source, connecting at least the motor and an output member, an engine clutch connecting the engine and the motor directly or indirectly, and fastening the engine clutch In a hybrid vehicle comprising a hydraulic pressure command value calculation means for commanding a hydraulic pressure to be adjusted, and an engine start control means for engaging the engine clutch and starting the engine,
Before SL engine start control means, when starting the engine, if it becomes larger than the clutch input rotational speed actual engine speed is the motor side speed of the front disappeared engine clutch to increase the slip amount of the engine clutch An engine start control device for a hybrid vehicle. In the hybrid vehicle engine start control device according to claim 1,
A target engine speed setting means for setting a target engine speed that is equal to or lower than the clutch input speed;
The hybrid vehicle engine start control device, wherein the engine start control means sets the hydraulic pressure command value based on a deviation between the target engine speed and an actual engine speed. In hybrid vehicle engine start control apparatus according to 請 Motomeko 2,
The engine start control device for a hybrid vehicle, wherein the target engine speed setting means sets a lower limit value for the hydraulic pressure command value. In the hybrid vehicle engine start control device according to claim 3,
When the engine start control means shifts from the released state of the engine clutch to the engaged state, the precharge phase for outputting the precharge hydraulic pressure command value until the clutch piston stroke is completed for the engagement pressure control, and the actual engine speed A feedback control phase that outputs a hydraulic pressure command value that matches the target engine speed, and
The engine start control device for a hybrid vehicle, wherein the target engine speed setting means sets the lower limit value to a hydraulic pressure command value during the feedback control phase. The engine start control device for a hybrid vehicle according to any one of claims 2 to 4,
An engine complete explosion determination means for determining that the engine is in a complete explosion state when the actual engine rotation speed is higher than the target engine rotation speed by a set value or more;
The engine start control means switches the engine control mode from the engine mode at start-up to the engine mode after complete explosion when it is determined that the engine is in a complete explosion state. . In the hybrid vehicle engine start control device according to claim 5,
The engine complete explosion determination means determines that the engine is in a complete explosion state when a state where the actual engine speed is higher than the target engine speed by the set speed or more continues for a first set time or longer. An engine start control device for a hybrid vehicle. The engine start control device for a hybrid vehicle according to any one of claims 2 to 6,
The engine start control device for a hybrid vehicle, wherein the target engine speed setting means sets the target engine speed to a higher value when the engine water temperature is low than when the engine water temperature is high. The engine start control device for a hybrid vehicle according to any one of claims 2 to 7,
The engine start control device for a hybrid vehicle, wherein the target engine speed setting means sets the target engine speed according to a clutch oil temperature. The engine start control device for a hybrid vehicle according to claim 6 ,
The engine start control means shifts to a ramp control phase in which the hydraulic pressure command value is gradually increased when the difference between the actual engine speed and the clutch input speed is equal to or less than a first deviation. Engine start control device. In the hybrid vehicle engine start control device according to claim 9,
The engine start control means shifts to a ramp control phase for gradually increasing the hydraulic pressure command value when a time during which the difference between the actual engine speed and the clutch speed is equal to or less than the first deviation continues for a second set time or longer. An engine start control device for a hybrid vehicle. A driving force generating transmission having an engine and a motor as a driving force generation source, connecting at least the motor and an output member, an engine clutch connecting the engine and the motor directly or indirectly, and fastening the engine clutch In a hybrid vehicle comprising a hydraulic pressure command value calculation means for commanding a hydraulic pressure to be adjusted, and an engine start control means for engaging the engine clutch and starting the engine,
The engine start control of a hybrid vehicle , wherein the engine clutch slip amount is increased when the actual engine speed becomes larger than a clutch input speed which is a motor side speed of the engine clutch. Method.

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